SHELL2 - A PACKAGE FOR THE CALCULATION OF 2-LOOP ON-SHELL FEYNMAN DIAGRAMS IN FORM

The description of a program written in FORM for the analytic calculation of propagator-type one- and two-loop Feynman graphs with external lines corresponding to massive as well as massless particles on-shell is presented. Dimensional regularization to regularize both ultraviolet and infrared divergences is used. The program calculates the contributions from any such diagram for an arbitrary value of the space-time dimension n in terms of one "master integral" and two simple integrals expressable in terms of Euler's GAMMA function. The package can be used for the calculation of anomalous magnetic moments of fermions, renormalization Constants in the on-shell renormalization scheme, the effective field theory of static quarks and other problems. As an example of an application the two-loop coefficient for the anomalous magnetic moment of the electron in QED is reproduced in the framework of dimensional regularization.